The lobster stomatogastric nervous system is a well-characterized neural network capable of generating rhythmic motor patterns operating the stomach musculature. This proposal seeks to determine the mechanisms underlying burst generators in this system, particularly how it is turned on and off and how it is modulated by sensory feedback loops. In addition, the behavior of the muscles will be defined in terms of dynamic range and the interaction of the stomatogastric rhythm with rhythms generated by other ganglia in the foregut nervous system will be studied. This system, we hope, can serve as a model for locomotion and other rhythmic patterns found in more complicated nervous systems. BIBLIOGRAPHIC REFERENCES: The selective staining of invertebrate nerve cells (1976) Allen I. Selverston, Scientific American (in press). The stomatogastric ganglion: A model system for the study of rhythmic behavior. (1976) Allen I. Selverston. In: Simple Networks: An Approach to Patterned Behavior and its Foundations, J. Fentress, ed., Sinauer, New York (in press).